Grado driver mod? - Page 7

You guys should do the damping mod I did. Simply glue foam in the inside of the cup, but a thin layer. Helps kill resonances and makes the headphone sound smoother.

This mod does make the sound better.

I used a broiler pan. I boiled some water, filled the pan and then put my Grado cups on the hole-ridden sheet that hovers over the pan. The steam and heat were enough to loosen the glue without doing any damage at all to the cups. This is a step forward from my first attempt, with a different set of earphones. I put those into a half-inch of hot water and ended up warping the plastic.

Before the mod, I could easily tell the difference between all my better Grados - including my Goldies, my RS-1 and my GS-1000. After the mod, they bested my Goldies and my RS-1's and gave my GS-1000s a run for their money. The GS-1000s probably do have a different driver or some kind of doping that helps them get their deeper bass. With the backs off and a clear infinite baffle, these SR-60s sound as open as the RS-1's. With a pair of salad-bowls superglued to the headband forks, I can hear the subtle difference in bass between the SR-60s and the GS-1000s.

But . . .

You can't really hear the GS-1000 in all its glory from an iPod. That little difference in distance between the ear and the driver opens up the soundstage and broadens the space, but that means that you have to crank it almost to the very top of the iPod's volume to get a "full" sound. Even then, you're not getting the full bass. When I pumped my GS-1000s through my M^3 with variable bass boost, they throbbed. All issues of sibilance went out the door.

With the salad bowls, my SR-60s had a similar problem running off the iPod. In fact, it was with the salad bowls that I was able to more fully detect the difference between them and the GS-1000s. But when I pumped them through my M^3, they sounded like the GS-1000s. That gap in bass filled up and these sub-$100 cans throbbed just like the GS-1000s. I still need to apply damping to the rear of the transducer and the inside of what's left of the air chamber. I hope it will help reduce spiking in the high midrange/low treble and smooth things out a little more. Only time will tell.

The cups on Grados are there to protect the drivers. They're supposed to be as open as possible while maintaining good sound. When I took the cups off of my MS1i's, I held the driver assembly (with quarter mod comfies) up against my ears and they sounded really fantastic. But I knew that I'd destroy the drivers somehow being the careless person that I am.

What I ended up doing was peeling off the tar from some Dynamat Extreme and spreading that gob over the back of the driver magnet being careful to leave the holes on it open. Then, I lined the cup with Dynamat and put a thin layer of felt onto that. It did make the headphones sound smoother, but it also ate away at the highs that make the Alessandros fantastic, so I removed the felt. With the lining on the cups and goop on the driver, the bass goes lower and is considerably cleaner, none of that mud. All of this IMO of course.

The outer cups also have the two holes to which the yoke (c-shaped plastic cup holder) attaches. Without it, you won't be able to use the headband assembly unless you drilled two new holes in the inner cup and used longer pivot pins.
If one were to want maximal "openess," you would break off the plastic grill (the one inside the outer cup). You can replace the stock plastic grill with a metal more perforated one like the SR225 and higher models for protection.

I used a blow drier to open the cans, glob of silicone adhesive on the transducer back, hot air on them to re-glue the cans. Sound does seem to be a bit tamer, but it's hard to tell because you can't exactly A/B the difference.

Then you wouldn't have the protection :P

I bought some SR-80s off a guy. They were supposed to have a problem in the cables, a problem I could fix. Instead, they were unfixable and I paid $34 for a boat anchor. But where life closes a door, it opens a window, right?

Well, I autopsied those phones - trying to fix them - and made some interesting discoveries, discoveries I wouldn't have made with phones I was worried about breaking. One of those discoveries was the nature of that centerpiece you spoke of.

Is it the magnet? Yes and no.

It's actually the magnet plate, for lack of a better term. The magnet fits right into it, which provides a place/space for the ribbon coil. I popped the assembly out, thinking this was a magnet with a groove cut into it. It was by chance that I got the two apart. The relationship between the magnet and the plate is much like that between a cup and saucer.

When you dampen the plate, what you're doing is absorbing the vibrations so they don't become part of the sound signature. While the plate pops right out of the back of the driver assembly, there may be some extent to which this metal plate oscillates in response to the vibrations to which it, itself, is exposed. I don't know how much an undampened plate may add to the HF signature of the Grados, but damping it is relatively easy. Since there are already consumer products readily available, in the world of audio sound, your options are pretty much wide open.

Very interesting!

What else did you discover? Also, do you have any pictures of the headphones disassembled? Perhaps we can turn this into an opportunity to figure out if Grado really does use the same drivers with all of their headphones (besides the GS and PS), and what kind of tweaking do they use to create the differences in sound between models.

Oh, and if you could open some Gradossandros, too...

xD

I have to go out of town today but when I get back, I'll post pics of the SR80 drivers disassembled. John Grado says the drivers are different, though what he means by "different" is anybody's guess. To a certain extent, the architecture of the Grado drivers is the same. They're all circular, using a vented mylar diaphragm, with small magnets, vented back plates and screens fore and aft. With the exception of the iGrado, they all have the same sensitivity. They have the same impedence. Grado's performance stats show different frequency ranges, but it's not clear where those numbers are coming from and to what extent they're taking into account the differences from additional items such as the wiring in the cord, the cushions used, the material in the air chambers and/or the type and material of the back grills.

To be sure, the drivers all look the same but the mylar can come in different thicknesses; diaphragms can be doped; screens can have different characteristics and the voice coils can have different gauges or types of wiring. Looking at the drivers in the iGrado, SR-60 and SR-80, I didn't notice any difference, but maybe those drivers are all the same and the differences are between them and some of the higher-ups, like the RS-1, the GS1k and the PS1k. What I do know is that what you do with the driver can make a substantial difference in the presentation.

I know this thread is a couple months old and hasn't been updated but just wanted to share what I did very recently with my SR80i's drivers and enclosures using cut up felt pads. Easy to do and increases resolution and imaging VERY noticeable! With the quarter modded stock S-Cush pads and new metal grill, these cans sound great! I'd love to still check out some higher Grado models like a SR225 to compare sometime.

Anyway, here goes from another post I started...

Update 3/23/2010...

My simple DIY driver and driver enclosure damping with felt adhesive pads that I cut out. I can really tell highs are much smoother and less harsh. Electric guitars especially in rock and metal music is smoother and crunchier. Resonance is lessened a small bit and sounds are more precise and to the point, almost as if instruments sound a little more 3D or binaural. I would call it much better imaging and resolution. I can place different sounds,vocals, instruments in space more precisely. Volume sounds lessened a little though...maybe about 5-10% or so. Not sure why. Maybe less resonance and reverb within the enclosure or on the drivers? Pink Floyd, rock and progressive trance sounds amazing! Of course, it's depends on the music source and recording. Overall, I like this cheap, basically free mod.

Random revival...
 

The plate likely adds resonance and acts as a secondary diaphragm. Without getting into the math and oversimplifying things, assume that your harmonics occur when your wavelength and plate are near the same size (plus round multiples or factors of each other), which mostly puts us into the high frequency range. The plate will either add or detract, depending on the frequency, which probably accounts somewhat Grado's unique sound. Damping the plate should smooth that out and give you a more "pure" sound from the driver (no guarantees if this is "better"). If nothing else, it should flatten the frequency response curve a bit.

Interesting. Are not some Grado's using a dampening material on this plate already?

jk

 

 

The magnet plate is not intended to be a secondary diaphragm.  It's intended to hold the magnet, which is necessary to the creation of a magnetic field, which is necessary to make the diaphragm react to the current running through the voice coil.  Nothing is more hyped and yet simpler than a headphone driver.  The potato chip bag (mylar) has a low mass, allowing it to be faster than the old paper cones.  It's form fit to oscillate in reaction to changes in the electromagnet field produced by the magnet and the voice coil.  The magnet is a cheap dynamic costing less than $1 retail.  The voice coil is just high gauge (very thin) copper wire.  The best voice coil is "flat wire" rolled together a few mm wide.  The voice coil is run from the magnet and glued to the diaphragm.  It's a fragile assembly but hardly complex.  Its most sophisticated aspect is the shape of the mylar, which has built-in ridges that look like a shrimp plate.  These ridges give the diaphragm borrowed rigidity for bass.  The center of the diaphragm also a built-in ring to facilitate the employment of the voice coil.

 

With regards to the magnet plate, the only reason it's metal is to help it hold the magnet, which sticks to it without any glue.  You can actually take a screwdriver and pop the cheap magnet out of the plate.

 

As for the bloated claims of the other top headphone manufacturers, ring magnets are not much more expensive.  Grado could employ a ring magnet and completely do away with the back plate.  It would take some retooling, however.  

 

Grado employs a dab of dynatek-style damping on the magnet back, a dab big enough to damp the free ringing of the magnet back without covering up the two ventilation holes.  I came up with my own cheap-and-dirty felt damping that doesn't cover the holes.  It looks like this:

 

Edited by Bilavideo - 7/11/10 at 6:33pm